Which of the following is the unit digit in the product of [(341)⁴⁹¹ × (625)³¹⁷ × (6374)¹⁷⁹³]?

Which of the following is a prime number?

The unit digit in the product (281 × 15 × 16 × 18) is :

What is the digit in the unit place of (232)³³?

Which among the following is NOT a prime number?

The value of a 2-digit number is 5 times the sum of the digits. What is the product of the digits ?